Dietitians Dish: Before exercises, consume energetic meals

Eating healthily is extremely important to be able to perform to your full potential when you exercise.

I am frequently asked which foods are the best to eat before exercising. Here are some things to keep in mind when choosing pre-exercise snacks.

Pre-exercise meals or snacks have four main functions. First, snacks help prevent hypoglycemia (low blood sugar). Symptoms of hypoglycemia include light-headedness, needless fatigue, blurred vision and indecisiveness, all of which can interfere with performing your best.

Additionally, they help settle your stomach, absorb some of the gastric juices your stomach produces and prevent you from feeling hungry during your work out.

Snacks also help ease your mind knowing that you are well-fueled and prepared for exercise.

Perhaps the most important purpose of pre-exercise meals is to provide energy to your muscles, with food eaten far enough in advance to be digested and stored as glycogen, what your muscles use for fuel during exercise.

Whether eating before you exercise or before an athletic event, try to allow three to four hours for a large meal to digest, two to three hours for a smaller meal to digest, one to two hours for a blended or liquid meal to digest, or 30-60 minutes for a small snack to digest. You should allow more time for digestion before very intense exercise compared to low-level activity.

So what exactly should you eat for a pre-exercise snack? Snack composition should be high in carbohydrates, moderate in protein and low in fat and fiber. Choose high starch, low fat goods such as bread, English muffins, bagels, crackers, pasta because these tend to digest easily, settle comfortably, and maintain a stable blood sugar. Small servings of low fat protein can settle well.

At your meals, it is better to choose high fiber carbohydrates such as whole grains because they digest slowly and keep you full for a longer period of time.

However, the purpose of snacks is to provide energy quickly. So avoiding the slowly digested carbohydrates like whole grains may be beneficial for pre-exercise snacks.

There are also certain foods that are not recommended before exercising. High-fat foods should be avoided because fats slow gastric emptying. Examples of high-fat foods include high-fat meat (i.e. bacon), heavy sauces/creams, fried foods, buttery foods, desserts, peanut butter and nuts.

Sugary foods such as soda, candy, syrup, fruit juice, etc., should also be avoided within an hour of exercise.

You may think the sugar gives you an energy boost, but you are likely to have a sugar low once you start your workout. This hypoglycemia (low blood sugar), can leave you feeling light-headed and fatigued.

Also, be cautious if you decide to consume a liquid snack, such as a protein shake. Liquid foods leave the stomach faster than solid foods, so they do not need as much time to digest. Some people feel nauseated when consuming liquid meals prior to exercise because it sloshes around the stomach.

Here are some examples of simple, healthy pre-exercise snacks to try.

Two tablespoons of low fat cottage cheese with one half of a cup of fruit

Three-fourths of a cup of unsweetened cereal with one half of a cup of low-fat or fat-free milk

Spread one to two tablespoons of low-fat yogurt on a waffle

Two to three thin slices of turkey or chicken on a piece of bread

Dip one half of a banana in low-fat yogurt and roll in crushed, unsweetened cereal. (This one is very tasty if frozen the night before.)

Keep in mind that if you have had a meal within the time frames listed above or are not participating in a very intense workout, you may not need a snack at all. See how you feel during your work out, and adjust your regimen as needed. As always, don't forget to stay hydrated.

Lindsay Adams is a registered dietitian. Send questions or comments to dietitians@vicad.com.